Oz is suspected of being a mole working for a drug lord. He finds himself a prisoner, by his boss determined to make him talk. For this he uses Laly, a naive young woman, very fragile, who proves to be a killer out of the ordinary, then Tony Sagaz, a black man of Scottish origin, a typical executioner, using his natural gifts as tools of torture. But this strategy of intimidation is not successful: Oz is too tough. The Boss has a plan B, a terrible secret weapon... 'The Mace'. Faced with this human machine, Oz will confront its own weaknesses.